简谐振动系统的振子质量为2.0kg，系统振动频率为100Hz，振幅为0.5cm，则其振动总能量为_____J。
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如果从冷兵器中选出一位绅士，那一定非剑莫属。If you want to ___ like weapon, the sword jian is ____.
在古代，剑是身份地位的象征。In ____, jian was a ____ of ____.
贵族不仅要学习文化还要学习剑术。Nobles not only had to study ____ but also ____.
铸造一把好剑需要复杂的工艺。A good jian is cast using ____.
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